With the development of consumer electronic products such as mobile phones and electronic compasses, additionally together with conventional products such as motors and brakes, the demand of magnetoresistance sensors is progressively increasing.
Typically, a magnetoresistance sensor includes a substrate, a magnetoresistance structure formed on the substrate and at least one conductive layer formed on the magnetoresistance structure, and in a conventional process for fabricating the magnetoresistance sensor, the magnetoresistance structure is firstly formed prior to the metallization process for forming the magnetoresistance structure. Such processing sequence leaves a high risk of cross contamination either to the backend equipments or front-end devices (in the substrate) due to the outward diffusion of the magnetic elements (for example iron, cobalt and nickel) in the magnetoresistance structure. The other concern of the conventional processes arises from thermal and stress accumulation contributed from the subsequent metallization processes, such as forming the conductive layer. The performance and reliability of the magnetoresistance structure may also get worse under such circumstances.